There is not, I think, any sufficient proof that mercury directly promotes the absorption of effused liquids. So far as it increases secretion, and thus lessens the volume of the blood, it may indirectly produce the effect; and may, therefore, in cases of excessive ptyalism or biliary evacuations from its use, have sometimes operated beneficially upon this principle; but assuredly no one would aim at producing absorption through such an agency. Although, therefore, mercury has been recommended in dropsy upon this ground, and has been much used in that disease, I do not think that it is calculated to be of any service whatever, so far as the mere absorption of the effused liquid is concerned. it has, indeed, been too indiscriminately employed in that affection; and has sometimes acted very injuriously by impairing the state of the blood, or otherwise debilitating, in cases where influences of a directly contrary character were all-important. in the dropsy of pure anaemia, and that dependent on fatty degeneration of the kidneys, it can do only harm. But there are undoubtedly cases of this affection in which it is extremely useful, not to say indispensable; and it is, therefore, of the greatest importance to make a proper discrimination. The varieties of dropsy to which it is adapted will be mentioned in another place. All that I wish to call attention to here, is that it should not be used indiscriminately in the affection, on account of any supposed property of favouring the absorption of effused liquids.

But mercury is very useful by promoting absorption in another way. it has long enjoyed great credit as a deobstruent, in resolving and dispersing chronic indurations and tumefactions of various kinds, such as enlarged glands, thickened ligaments, osseous swellings, inflammations, hardenings, and hypertrophy of the different tissues. So far as still existing inflammation has anything to do with these conditions, mercury may be supposed to act simply through its antiphlogistic property. But it proves useful when all signs of inflammation have disappeared, and sometimes, perhaps, when there is no proof that it has ever existed. it seems in these cases to exercise a direct power of absorption. The effect may be explained without difficulty, in accordance with the views already given of the action of mercury. One of its most energetic properties is that of promoting disintegration of the tissues. it may be readily conceived to exert this property, with greater relative effect, on structures having little vital power of resistance, than on those which are quite healthy. if this be the case, swellings and indurations of the kind referred to, having comparatively feeble vital force, yield to the disintegrating influence with greater facility, and are consequently diminished more rapidly than the structure around them. Of course, the debris of the tissues are carried off by the absorbents, or veins, and absorption seems to have been promoted; the fact, however, being, that this function is stimulated by the effete matters of the decomposed structures, and not that the structures disappear through increased activity of absorption.

As an example of the good effects which may be expected from this property of mercury, beyond the mere removal of the tumefaction, may be adduced the relief of serious organic affections of the heart. in consequence of the organization of the fibrinous exudation of endocarditis, thickening of the valves, and excrescences upon their surface are apt to remain, either impeding the onward flow of the blood, or, through imperfect closure of the valves, giving rise to regurgitation. Hence hypertrophy and dilatation of the heart, congestion and consequent disease of the great viscera, and ultimately universal dropsy. in such cases, indicated by abnormal sounds of the heart, if treatment be commenced before serious mischief has been accomplished, there is reason to hope that a moderate but steady course of mercury may prove of great service, by effecting a removal of the offending cause.

In all cases of external hardening and tumefaction, the mercury may be used both internally, and by friction with the ointment or the application of the mercurial plaster, externally; the topical use of it being so directed, that the absorbed medicine may be made to pass into the abnormal structure.